Buggy code:
public class WebServiceSamplerGui extends AbstractSamplerGui implements ActionListener { JLabeledTextField urlField = new JLabeledTextField ( JMeterUtils . getResString ( "url" ) ) ; JLabeledTextField soapAction = new JLabeledTextField ( JMeterUtils . getResString ( "webservice_soap_action" ) ) ; JLabeledTextArea soapXml = new JLabeledTextArea ( JMeterUtils . getResString ( "soap_data_title" ) , null ) ; JLabeledTextField wsdlField = new JLabeledTextField ( JMeterUtils . getResString ( "wsdl_url" ) ) ; JButton wsdlButton = new JButton ( JMeterUtils . getResString ( "load_wsdl" ) ) ; JButton selectButton = new JButton ( JMeterUtils . getResString ( "configure_wsdl" ) ) ; JLabeledChoice wsdlMethods = null ; WSDLHelper HELPER = null ; FilePanel soapXmlFile = new FilePanel ( JMeterUtils . getResString ( "get_xml_from_file" ) , ".xml" ) ; JLabeledTextField randomXmlFile = new JLabeledTextField ( JMeterUtils . getResString ( "get_xml_from_random" ) ) ; JLabel wsdlMessage = new JLabel ( JMeterUtils . getResString ( "get_xml_message" ) ) ; JLabel wsdlMessage2 = new JLabel ( JMeterUtils . getResString ( "get_xml_message2" ) ) ; JLabel wsdlMessage3 = new JLabel ( JMeterUtils . getResString ( "get_xml_message3" ) ) ; JLabel wsdlMessage4 = new JLabel ( JMeterUtils . getResString ( "get_xml_message4" ) ) ; JLabel wsdlMessage5 = new JLabel ( JMeterUtils . getResString ( "get_xml_message5" ) ) ; Font plainText = new Font ( "plain" , Font . PLAIN , 10 ) ; JCheckBox memCache = new JCheckBox ( JMeterUtils . getResString ( "memory_cache" ) , true ) ; JCheckBox readResponse = new JCheckBox ( JMeterUtils . getResString ( "read_soap_response" ) ) ; JCheckBox useProxy = new JCheckBox ( JMeterUtils . getResString ( "webservice_use_proxy" ) ) ; JLabeledTextField proxyHost = new JLabeledTextField ( JMeterUtils . getResString ( "webservice_proxy_host" ) ) ; JLabeledTextField proxyPort = new JLabeledTextField ( JMeterUtils . getResString ( "webservice_proxy_port" ) ) ; JLabel readMessage = new JLabel ( JMeterUtils . getResString ( "read_response_note" ) ) ; JLabel readMessage2 = new JLabel ( JMeterUtils . getResString ( "read_response_note2" ) ) ; JLabel readMessage3 = new JLabel ( JMeterUtils . getResString ( "read_response_note3" ) ) ; JLabel proxyMessage = new JLabel ( JMeterUtils . getResString ( "webservice_proxy_note" ) ) ; JLabel proxyMessage2 = new JLabel ( JMeterUtils . getResString ( "webservice_proxy_note2" ) ) ; JLabel proxyMessage3 = new JLabel ( JMeterUtils . getResString ( "webservice_proxy_note3" ) ) ; public WebServiceSamplerGui ( ) { } public String getLabelResource ( ) { } public TestElement createTestElement ( ) { } public void modifyTestElement ( TestElement s ) { } private void init ( ) { } public void configure ( TestElement el ) { } public void configureFromWSDL ( ) { if ( ( HELPER . getBinding ( ) ) != null ) { this . urlField . setText ( HELPER . getBinding ( ) ) ; } else { StringBuffer buf = new StringBuffer ( ) ; buf . append ( ( "http:////" + ( HELPER . getURL ( ) . getHost ( ) ) ) ) ; if ( ( HELPER . getURL ( ) . getPort ( ) ) != ( - 1 ) ) { buf . append ( ( ":" + ( HELPER . getURL ( ) . getPort ( ) ) ) ) ; } else { buf . append ( ( ":" + 80 ) ) ; } buf . append ( HELPER . getURL ( ) . getPath ( ) ) ; this . urlField . setText ( buf . toString ( ) ) ; } <START_BUG> this . soapAction . setText ( HELPER . getSoapAction ( ( ( String ) ( this . wsdlMethods . getText ( ) ) ) ) ) ; <END_BUG> } public String [ ] browseWSDL ( String url ) { } public void actionPerformed ( ActionEvent event ) { } }

Fix:
this . soapAction . setText ( HELPER . getSoapAction ( this . wsdlMethods . getText ( ) ) ) ;